The invention relates to a pen of the type stated in the preamble to claims 1 and 19. Moreover the invention relates to a method for removing a pen point according to the preamble to claim 16 and a clip according to the preamble to claim 20.
A type of pen which occurs frequently on the market has a pen body with an ink stick which is removably arranged therein and which at its one end has a pen point and is insertable and extractable through the open end of the pen body. An ink cartridge with a pen point is referred to as ink stick. Access is gained to the ink stick by removing a nose cone which is screwably arranged on the front part of the pen body and which, when being unscrewed, leaves such a long part of the cartridge behind that the user can remove the cartridge by hand from the pen body when, for instance, exchanging the cartridge. The nose cone has a plurality of drawbacks. It must be unscrewed, which makes the exchange of the ink cartridge difficult. The nose cone is a loose part which can easily be lost when exchanging the ink cartridge. Moreover the nose cone makes the manufacture of the pen more expensive.
U.S. Pat. No. 4,952,088 shows how a clip arranged on the cap of the pen can be used for form-fit engagement with a specially adapted nose cone, the clip/cap serving as a lever to unscrew the nose cone from the pen body. A problem of the clip according to U.S. Pat. No. 4,952,088 is that the pen point must be specially designed or alternatively must be combined with a nose cone. Moreover the possibilities of designing the pen are limited by the construction of the clip.
EP-0 657 301 A1 shows how a pen point can be extracted from a pen body with the aid of an engaging means arranged on the cap. The engaging means is designed for form-fit engagement with a specially adapted groove in an adaptor sleeve mounted around the pen point. Some problems of the engaging means according to EP-0 657 301 A1 are its restriction of the possibilities of designing the pen, the risk of it getting stuck, for instance, in the user""s clothes, and the necessary cooperation with a specially adapted adaptor sleeve.
Besides conventional writing materials, also so-called digital pens have recently been developed, which contain sensors and electronics for digital recording of what is being written by means of the pen on a base. Different types of sensors can be arranged in the pen for determining its position, for instance acceleration sensors, as disclosed in U.S. Pat. No. 5,434,371 and U.S. Pat. No. 6,130,666, optical sensors, as described in U.S. Pat. No. 5,294,792, U.S. Pat. No. 5,852,434 and WO 00/73983, pressure sensors, as described in U.S. Pat. No. 6,104,388, or mechanical sensors, as described in U.S. Pat. No. 5,294,792 and U.S. Pat. No. 6,130,666. For reasons of security, the pen body of such digital pens is frequently designed to prevent access to the interior of the pen and the sensitive components therein. The ink stick is therefore inserted into a duct extending into the pen body from its writing end. Like in ordinary pens of this type, it is difficult for the user to exchange the ink stick, whether the pen has a nose cone or not.
Thus the present invention relates to a pen of the type described by way of introduction, which solves the above problems, the pen having obtained the features as defined in the respective characterizing clauses of claims 1 and 19.
The present invention further relates to a method for removing a pen point of the type described above, the method having obtained the features as defined in the characterizing clause of claim 16.
The present invention also relates to a clip for holding a pen of the type described above when carried in a user""s pocket, the clip having obtained the features as defined in the characterizing clause of claim 20.